Marking up text is a methodology for encoding data with information about the data. Data without context lacks meaning. In order to send data through computers and programs, the data needs to have information with it that explains that what the data means and/or how the unit receiving the data should handle the data.
HyperText Markup Language (HTML) was one of the first markup languages utilized. HTML defines a set of tags that associate formatting rules with portions of text. An HTML processing application such as a web browser is used to read the data and its formatting tags and to display the text in accordance with predefined rules. Since the rules that define the tags are universally known for HTML, the data may be sent over the Internet to virtually anyone and will be displayed in a predetermined fashion based on the HTML rules governing the tags.
Extensible Markup language (XML) was developed because web designers wanted more control over presentation of their data. That is, rather than be restricted to a limited set of tags defined by standards bodies, users in particular businesses wished to be able to develop their own business-specific tag sets to meet their own unique needs without requiring all other users to have a browser that incorporated the functionality for displaying data according to all known business-specific tag set rules. In this manner, each business or industry was able to develop tools that met their own specific needs. In addition, the tags for XML do not need to be limited to formatting rules (as with HTML). Such a system allowed each business or industry to utilize its own terminology for its tags, thus allowing a choice of tags from a larger pool of terms than would be possible if everyone were dealing with a single set of tag rules. Thus, XML is a markup language that uses rule-specifying tags developed by a particular business or industry and has an associated tag-processing application that implements the rules associated with the tags. Hence, XML is an meta-markup language that permits construction of an unlimited number of markup languages based on XML standards, and the rules for the tags may represent data relationships, business rules, or whatever rules the designer wishes.
XML requires a syntax for marking up the data and a defined method of handling the marked-up data. In XML, the definition of a valid markup is provided by a Document Type Definition (DTD) that specifies the structure of the markup language, i.e., how the data is to be marked up. In order to specify what valid tags mean, XML documents have associated therewith style sheets that provide graphical user interface (GUI) instructions for the processing application, e.g., a web browser. The processing application combines the DTD, the logic of the style sheet, and the data to display the data in accordance with the syntax and the defined method.
In early work, Standard Generalized Markup Language (SGML) was developed as an international standard for marking up data. Though SGML was a powerful, extensible tool, it is complex and expensive. If SGML were to have a word processor added to it, SGML would become extremely expensive. The World Wide Web Consortium (W3C) sponsored a group of developers, who simplified the SGML to a format that has evolved to become today's XML. In this manner, a relatively non-complex markup language, XML, was established as an approved language for marking up data.
XML opened up the possibility of providing data that could flexibly be reconfigured from a list to a table without an undue amount of editing of the coding since the GUI was extracted, allowed searching data using data relationships, and improved the portability of data by providing the capability of presenting data that did not have HTML tags that needed to be stripped out when the data was put into, for example, a Java applet. Of course, the drawback is that XML documents must be precisely entered, generally termed “well-formed”, into the system because, if the syntax is incorrect, the XML file will simply generate a “fatal error” message. In XML, a “well-formed” document follows the XML syntax rules so that it is readable by a computer. That is, since HTML documents have standard tags, the browsers often have built-in recovery codes that “guess” if a tag is missing at the beginning of an HTML document. In XML, since structured data is used with non-standard tags, the parser typically cannot guess what is missing if a tag is missing.
Since XML documents do not use universally standardized tags, may not contain formatting information, have no application semantics and may need to be presented in a form other than the form transmitted, the XML document needs to have additional information included that sets forth how the information is to be presented or processed. Separation of style from content allows for presentation of the data in more than one way. Style sheets specify the presentation of XML data using two techniques: an optional transformation of the input document into another structure and a description of how to present the transformed information. Because style sheets are extracted from the data, the style sheets may be shared by XML documents and may be written in any selected style language such as, for example, Cascading Style Sheet Language (CSS) or extensible Style Language (XSL).
The XSL language logically consists of three component languages: XPath, XSLT and XSL. Xpath is an XML Path Language for referencing specific parts of an XML document. XSLT is an XSL Transformation Language for describing how to transform one XML document that is represented as a tree into another XML document. XSL is an Extensible Style Sheet Language that uses XSLT together with a description of a set of formatting objects and formatting properties. An XSL style sheet transforms the input document's tree into a result tree that consists of results objects, which may, if desired, be serialized and may be used to write out the document as an HTML document, an XML document in another document type or may match a set of formatting objects and formatting properties. An XSL style sheet contains at least one template, and may have a set of templates that match a set of elements in the source tree and describe the contribution that the matched element makes to the result tree.
In addition to the physical structure, XML documents have a logical structure. Logically, documents include declarations, elements, comments, character references, and processing instructions. The logical elements are indicated in the document by explicit markup. Markup language includes tags, comments, processing instructions, DTDs, references and the like.
Generally, an XML document begins with a declaration that is a processing instruction indicating to the processing agent that the document has been marked up as an XML document. Next, to code the document, one generally provides an element. An element is a basic unit of XML content that includes a start tag, character data and an end tag. The text within the tags is said to be “markup”, and proper case must be used (i.e., “NAME” is not the same as “Name”). For example, the following may represent an element: <NAME>John Doe</NAME>.
Other tag-based language formats have also been developed such as, for example, ColdFusion® Markup Language (CFML) format and a Wireless Markup Language (WML) format.
Traditionally, when a developer wished to change information in an application for operating a server, the application had to be shut down, the change entered, and the application restarted. There is a need for providing a method and system for adjusting an operating server application “on the fly”, i.e., without shutting down the server application so that the server can maintain efficiency and remain available to users while an application is being changed.